charseq.java

来自「java nio 编程一个实例子.服务端程序」· Java 代码 · 共 61 行

package com.ronsoft.books.nio.regex;

import java.nio.CharBuffer;

/**
 * Demonstrate behavior of java.lang.CharSequence as implemented
 * by String, StringBuffer and CharBuffer.
 *
 * Created: April, 2002
 * @author Ron Hitchens ([e-mail])
 * @version $Id: CharSeq.java,v 1.1 2002/05/07 02:21:08 ron Exp $
 */
public class CharSeq
{
	public static void main (String [] argv)
	{
		StringBuffer stringBuffer = new StringBuffer ("Hello World");
		CharBuffer charBuffer = CharBuffer.allocate (20);
		CharSequence charSequence = "Hello World";

		// derived directly from a String
		printCharSequence (charSequence);

		// derived from a StringBuffer
		charSequence = stringBuffer;
		printCharSequence (charSequence);

		// change StringBuffer
		stringBuffer.setLength (0);
		stringBuffer.append ("Goodbye cruel world");
		// same "immutable" CharSequence yields different result
		printCharSequence (charSequence);

		// derive CharSequence from CharBuffer.
		charSequence = charBuffer;
		charBuffer.put ("xxxxxxxxxxxxxxxxxxxx");
		charBuffer.clear();

		charBuffer.put ("Hello World");
		charBuffer.flip();
		printCharSequence (charSequence);

		charBuffer.mark();
		charBuffer.put ("Seeya");
		charBuffer.reset();
		printCharSequence (charSequence);

		charBuffer.clear();
		printCharSequence (charSequence);
		// changing underlying CharBuffer is reflected in the
		// read-only CharSequnce interface.
	}

	private static void printCharSequence (CharSequence cs)
	{
		System.out.println ("length=" + cs.length()
			+ ", content='" + cs.toString() + "'");
	}
}